"Linus Torvalds...is a terrible engineer" - Alan Cox

[Asher]

http://news.zdnet.co.uk/software/linuxunix/0,39020390,39189593,00.htm

The ups and downs of life with Linus
Ingrid Marson in Brussels
ZDNet UK
March 01, 2005, 18:15 GMT

FOSDEM: He may be the saint of the Linux community, but it sounds like Linus Torvalds - with his secret security fixes - could still be a challenge to work with

Linux kernel maintainer Alan Cox has given an insight into the experience of working with Linus Torvalds, the founder of Linux who maintains its development kernel.

During a talk last weekend at the Free and Open source Software Developers European Meeting, FOSDEM, on the challenges of maintaining a stable Linux kernel, Cox revealed that although Linus is good at developing code, he does not enjoy some of the other jobs that go along with software development such as bug fixing and beta testing.

"Linus is a good developer, but is a terrible engineer," said Cox. "I'm sure he would agree with that."

Cox explained that he and Torvalds sometimes have different approaches to fixing a problem, due in part to their different responsibilities. As the maintainer of the development kernel Torvalds needs make sure the kernel code is easy to maintain, while Cox is more interested in kernel stability and is not so worried about "hacking" the code to get it to work.

"One of the hard problems to fix are design errors," said Cox. "These are a pain because they need a lot of refactoring. Linus' approach is to re-write it to a better design. But to get a stable kernel you tend to do small horrible fixes. Linus is very keen to have maintainable code, while to have a stable kernel I'm keen to have code that works."

Cox said that Torvalds does not always let people know when he has fixed a security bug in the kernel. This can be a problem as the patch will take a while to make it to production, which means that hackers can exploit the vulnerability before it is made available to individuals and enterprises running Linux.

"Linus has this bad habit of fixing security holes quietly," said Cox. "This is a bad idea as some people read all the kernel patches to find the security holes."

Linux enjoys a reputation as a particulary secure operating system, compared to rivals such as Microsoft's Windows. Last month a mailing list was set up to help Linux kernel developers share information on security flaws.

Deciding what bugs to fix in the Linux kernel is not always easy, particularly as fixing it can impact other applications. Cox said he gives top priority to bugs that are reported soon after the release candidate is made available.

"Release candidates will pick out a lot of the stupid bugs, and what are plain stupid ideas," said Cox. "Two or three days after the release candidate we will have 150 emails with same bugs."

These early issues can be easy to fix as they are often obvious bugs. "Early problems you get are normally very easy to fix," said Cox. "As soon as the release comes out bug reports say 'You've broken this'. Almost immediately you go, 'Whoops, that’s my mistake'. Ten minutes later the fix is in the development tree."

But kernel bugs that appear easy to fix can be misleading. "Sometimes you see a fix and think 'this is perfect, move my fix into the kernel tree'," said Cox. "Later you think, 'I must have been drunk. Don't apply that patch'."

I've always been of the opinion that the Linux kernel design is both antiquated and a kludgey mess. Then again, that opinion may have been influenced by my OS Design prof who had only bad things to say about it...

It's nice to see that Alan Cox seems to agree. Not everyone involved in the development process lacks good judgement...

[Ari Rahikkala]

I hope you realised that whether you're right or not, your opinion has nothing to do with Alan Cox's opinion . The article didn't state anything about whether Linux's design is good or not, it stated that Linus is not a good engineer because he only really cares about hacking the code to make it better for further hacking, while a good engineer should try to keep the product stable and hunt bugs zealously.

Now, I actually disagree with Alan Cox. Torvalds is a good programmer, nothing remarkable as a computer scientist, though. He's much more remarkable as... wait for it... a manager and as an advertiser.

If you've ever read the LKML, you've probably noticed that one of the things that people just love doing there is flaming away at each other as if they had more time for inventing new, interesting kinds of verbal abuse than for developing the kernel. It's a very libertarian place and definitely chaotic at times, but the people there still manage to get things done. I don't really know how it works, and honestly my only guess is that Torvalds somehow figured out how to either attract only very thick-skinned people or make those who would get insulted by aspersions being cast on their skills grow a thicker skin. Nowadays he somehow manages the place by not really managing it at all...

As an advertiser... well, this is a bit simpler. That man keeps giving interviews and throwing soundbites left and right *under the pretense that all he's really interested in is hacking the kernel*. He spends hours convincing people that he's not spending hours convincing people about things, and for some reason it seems to work.

I'm not going to argue with you about the design or the quality of the kernel itself, BTW. I'll just leave you with this quote, after all, quotes make you smart :

"Dont forget that Linux became only possible because 20 years of OS research was carefully studied, analyzed, discussed and thrown away."
-- Ingo Molnar

[Asher]

I agree with the statement that he's not a good engineer, in that the software is not well-designed. He may be a good software developer, as in a programmer, but I don't think he's even very good with that, either.

I very much disagree with Ingo Molnar's quote, mainly because it doesn't make any sense. The purpose of Linux was a free Minix clone, and was started by an undergrad student and hacked and kludged from that point on. It's not because of 20 years of OS research that was studied, it was based on having a free clone of Minix with what basic OS knowledge a Finnish undergrad student has.

If Linus actually knew about making maintainble code, the last thing he would've done was opt for a monolithic kernel.

As for his management abilities, I again very much disagree. What evidence do we have for his abilities? The incredibly-delayed 2.4 kernel? The buggy, delayed release of the 2.6 kernel? The "secret" undocumented security fixes? The fact that he's a megalomaniac with a "what I say goes" attitude?

Ironically, it was Windows NT that started with the perspective of 20+ years or research and OS development, where the designers (who happened to be far more qualified than Linus) rethought a lot of the OS design and threw out what didn't work, and tried some new things.

You'll be hard-pressed to find someone who studies Operating System design at a high academic level to say the Linux kernel is a better design than the NT kernel.

[Whoha]

Linux has really improved in the last few years.

[MarkG]

my OS Design prof who had only bad things to say about it

this explains everything.....

[pchang]

Asher, you've really missed your calling. Your sensationalist thread titles show you should really be an editor at the National Enquirer.

[Asher]

Originally posted by MarkG

my OS Design prof who had only bad things to say about it

this explains everything.....

Yes, education and insight from someone with a PhD in that field explains a lot.

[Asher]

Originally posted by pchang
Asher, you've really missed your calling. Your sensationalist thread titles show you should really be an editor at the National Enquirer.

But it's a real quote. National Enquirer makes stuff up.

[pchang]

Originally posted by Asher

But it's a real quote. National Enquirer makes stuff up.

And that's why you would be better than their current editors.

[Asher]

Originally posted by pchang
And that's why you would be better than their current editors.

I'd fit in better at The Inquirer: http://www.theinquirer.net/

Headlines like: "AMD dual cores to be superfast"
"Spam helps cure AIDS"
"Sony puts beef into console bull terrier"
"Klingon cloaking device planned"
"Microsoft King gets British Knighthood"
"Ghost found in aisles at embedded show"

And that's just from today's front page...

[Agathon]

Yes, education and insight from someone with a PhD in that field explains a lot.

The first lesson of university is that people with PhDs disagree with each other - often vehemently.

[Asher]

Originally posted by Agathon
The first lesson of university is that people with PhDs disagree with each other - often vehemently.

Yes, but I've yet to find someone with credentials who would disagree with the assertion that monolithic kernels are frowned upon, and the Linux kernel is anything but well-designed.

[Ogie Oglethorpe]

Originally posted by Agathon

Yes, education and insight from someone with a PhD in that field explains a lot.

The first lesson of university is that people with PhDs disagree with each other - often vehemently.

Bring back dueling (including use of stand in grad students)

[Asher]

There's one quote alone that discredits Linus' engineering/design ability:

... message passing as the fundamental operation of the OS is just an exercise in computer science masturbation. It may feel good, but you don't actually get anything DONE.

That's a patently ridiculous statement, as the pseudo-microkernel Windows NT/2K/XP and fully-microkernel OS X show us.

[Agathon]

Bring back dueling (including use of stand in grad students)